In China, Luffa cilindrica is known as "sin qua". There are a number of distinct varieties of edible Luffa Gourd sold in southeast asia and India, where the greatest genetic diversity is found. There are varieties with angular or ridged fruit and smooth cylindrical types. They are most often considered two different species. Luffa acutangula is known in some parts of the southern U.S. as vine okra or Chinese Okra, the angular varieties do look a bit like okra when harvested young.
While the very young fruit can be sliced and added to salads where it gives a mild cucumber-like flavor, the fruit is esteemed in stir fry and in sauces because it has the ability to soak up the flavors and add texture. It is also batter dipped and fried. It is an interesting, easy to use edible squash. The kinds that I prefer have been developed for culinary use and are sweet or mild, non-bitter kinds. They are always eaten when young (before they reach 6" long) and while they are firm and solid because the older fruit develop fibrous interiors, tough skin and a bitterness which may be slightly toxic.
The Luffa is more acclaimed in this country for the fibrous interior of mature fruit which can be dried and used as a cosmetic bath sponge. There have been breeding programs at the University of North Carolina to develop good varieties for this purpose and to work out methods of growing and processing the fruit for cosmetic sponges.
While the Luffa is an old world tropical squash we have found some varieties that grow well on Long Island. They are rampant sprawlers that do well on a trellis. The large yellow flowers are bee pollinated. This year for the first time we were able to produce a large seed crop of an early ridged kind. Usually we manage to produce good food crops of the cylindric kinds but they tend to rot instead of dry on the trellis like the ridged kind.
The dry ridged gourds rattle with their enclosed black seeds. They are very tough with parchment like exteriors and tough cellulose fiber interiors. What a gourd! I'm not too interested in processing the fruit as a source of cosmetic sponge but I am told that it is quite lucrative. The golden ridged fruits that I strung up in bunches for seed created quite a stir because of their ornamental look. Maybe I could sell the gourds as an ornament and then tell my customers that when they're tired of looking at it, just soak it in water for a half hour and then peeling away the skin. Make your own sponge.